Description:

This work proposes to combine four analysis tools for measurement of environmental endocrine disrupting chemicals at concentrations relevant to exposure assessment. The plentiful chemical information resulting from endocrine disrupting chemical (EDC) mixture analysis according to our proposed scheme will elucidate the nature of unknown mixtures before and after they have interacted with the bioluminescent yeast bioreporter. This synergy of structural, kinetic, and separation information will enhance understanding of EDC behaviors regardless of whether the components in the mixture trigger yeast bioluminescence or not. Our work directly addresses two of EPA's three areas of interest ("development of analytical methods for the measurement of mixtures of EDCs in environmental media at relevant concentrations" and "development of rapid chemical or biological detection methods or technologies for environmental exposure monitoring"). By incorporating a bioreporter as a yes/no test for endocrine activity on the front end of the integrated microfluidic device, this work also builds on a biotechnology that addresses the third area of interest, "development of activity-based biological indicators for assessing EDC exposure in environmental media".

Objective:

The specific objectives of this study include (1) test an array of EDCs in environmentally /biologically relevant combinations and matrices for surface enhanced Raman spectroscopy (SERS) response characteristics to create a quantitatively rigorous spectral library; (2) develop nanomechanical response signatures of EDCs on microcantilever arrays (mCA) treated with molecular recognition phases (MRPs); (3) integrate bioreporter yeast into living conditions suitable for predictable function on a microfluidic platform and optimize those conditions with electrophoretic separation parameters for EDCs; and (4) validate a fully integrated microfluidic device that houses bioluminescent reporters of EDC presence, separations, and quantitative vibrational and nanomechanical detection of EDC-containing samples of known and unknown composition in "realistic" matrices.

Approach:

Utilized herein are two techniques, bioactivity-based bioluminescent yeast reporting and chemical separations, having already shown promise for analysis, mated with two powerful, informative sensing modes that employ novel nanomaterials and are relatively new to EDC detection, SERS and mCA sensing. This combination will provide environmental researchers with a device capable of qualitative indication of endocrine activity of an EDC mixture followed by efficient separations and quantitative vibrational information and/or nanomechanical transduction of the various chemicals in the mixture.

Expected Results:

The expected results include a validated assay to utilize a yeast model for endocrine exposure testing integrated into a microfluidic device capable of efficiently separating and yielding up to two different, structurally specific, quantitatively rigorous detection outputs (vibrational and nanomechanical) for an array of priority EDCs. Better analysis tools with integrated simple cells such as yeast for a model group of EDCs can be extended to mammalian cell lines and larger classes of EDCs; development of such tools and their attendant methodologies directly serves to assay latent environmental threats to public health such as endocrine disruption.

Progress and Final Reports:

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.